Igniter

ABSTRACT

An igniter has an electric filament and lead wires connected to the filament which are insulated but in intimate contact, the insulation being flammable and on burning of the insulation the wires short circuit, and a block of combustible material surrounding the filament and in contact with the insulation so as to ignite the insulation when the filament is energized.

United States Patent [72] Inventor Favian M. Adair P.O. Box 4206, Tyler, Tex. 75701 21 Appl. No. 872,985

[22] Filed Oct. 31, 1969 [45] Patented Oct. 26, 1971 [54] IGNITER 3 Claims, 4 Drawing Figs.

[52] US. Cl 44/36, 102/28 R, 102/702 R, 126/595, 431/98 [51] Int. Cl A0lg 13/06, F23q 21/00 [50] Field of Search 126/595; 431/95, 98; 102/28, 28 M, 70.2; 44/36 [56] References Cited UNITED STATES PATENTS 2,725,821 12/1955 Coleman 102/28 X 3,041,972 7/1962 Ball 102/28 M 3,445,204 5/1969 Bartlett et al. 126/59.5 X 3,459,487 8/1969 Glenn 431/95 Primary Examiner-Charles .l. Myhre Attorney.lackson, Jackson and Chovanes ABSTRACT: An igniter has an electric filament and lead wires connected to the filament which are insulated but in intimate contact, the insulation being flammable and on burning of the insulation the wires short circuit, and a block of combustible material surrounding the filament and in contact with the insulation so as to ignite the insulation when the filament is energized. 1

- IGNITER The present invention relates to igniters of inexpensive type which are are capable of providing heat or light and which are ignited in series from a source of electric current of moderate voltage.

A purpose of the invention is to replace relatively expensive and sophisticated ignition systems for smudge pots and the like by inexpensive igniters which can be ignited by a conventional battery which might be used on an automobile or truck or by a corresponding source of current of moderate voltage.

A further purpose is to provide that each of the series-connected igniters has lead wires for the filament coated with flammable insulation and in intimate contact because they are twisted together, the filament being in contact with a block of combustible material which is capable of igniting the igniter and also burning off the insulation so that it short circuits, thus reducing the impedance of the circuit by that amount and increasing the voltage available to ignite another one of the series-connected igniters.

A further purpose is to employ an igniter which is not subject to spontaneous combustion and will be resistant to ignition by contact with a spark or a match.

A further purpose is to provide an igniter whose electrical characteristics may vary over a very wide tolerance, so that its ignition time may vary by a matter of minutes, and yet which will reliably ignite in a reasonable time.

Further purposes appear in the specification and in the claims.

In the drawings I have chosen to illustrate one only of the numerous embodiments in which the invention may appear, selecting the form shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIG. 1 is a diagrammatic top plan view of an orchard to which the igniters of the invention have been applied.

FIG. 2 is a top plan view of an igniter of the invention.

FIG. 3 is a central vertical sectional perspective of the igniter of the invention.

FIG. 4 is a circuit diagram showing the connection of several igniters in series to a power source.

Describing in illustration but not in limitation and referring to the drawing:

The invention is directed primarily to an igniter of the type which will ignite heating elements or fuel distributed around an orchard to protect vegetation against frost, or for use as aircraft runway flares or as igniters for pyrotechnic displays.

In the further discussion, particular attention will be given to use in orchards because this is believed to be a very important and preferred use for the device of the invention.

At the present time many orchards protect against frost by oil-buming salamanders or smudge pots. In a large orchard these are very numerous and it is quite difficult to assemble enough men to light them at the required time. Ignition systems based on blasting detonators and on remote radio transmitters have been tried, but are very expensive.

The invention is intended particularly to protect citrus fruit such as oranges, grapefruits or lemons, other semitropical fruits such as avocados and also to protect buds and blossoms of temperate climate fruits such as apples.

The danger to be anticipated, particularly in the case of citrus fruit, is ruining of the crop and dropping of thefruit by freezing, and in a prolonged frost, damage to branches and damage to the trees.

It is necessary to maintain a temperature above 32" F. to protect oranges; above 34 F. for avacados and above 28 F. for grapefruit.

Weather-forecasting facilities usually provide only 6 or 8 hours notice of a freeze, and in the citrus growing areas, a typical freeze usually lasts not in excess of 8 hours. It is necessary to have the smudge pots lighted about 1 hour before the freezing air arrives and for proper protection the supply of heat for a time of 1 hour should be about 5,000,000 B.t.u. per acre. Recognizing that a large orchard may contain thousands of trees and that several smudge pots may be used per tree, it will be evident that to light all these smudge pots in a time of 4 hours requires a large labor force.

The present invention makes it possible to distribute and interconnect numerous igniters in a series circuit and to ignite each one of these igniter chains by connecting a source of power to it such as an automobile or truck battery of say 12 volts and leaving it in the circuit for a matter of a few minutes. in tests I have successfully ignited all of the igniters in chains of igniters using a l2-volt automobile battery.

FIG. 1 is a plan view of a portion of a citrus orchard having trees 20 distributed in regular rows and each tree surrounded by four heater units 21 of the invention connected in series as suggested by the dotted lines 22. Two rows of igniters are connected in series and provide two wires adjacent an access road 23 so that a truck passing along the road can ignite all the igniters in each chain, as by connection with a battery 33.

The heating units are preferably simple blocks of specially processed coal, charcoal or similar solid fuel which can rest on the ground, provide heat to a considerable extent by radiant energy and burn like embers for several hours once they are ignited. Each of these heating units can to advantage contain about 5 pounds of fuel. They have the further advantage that they create a minimum of smoke or air pollution and therefore are acceptable in communities which are very sensitive to damage to inhabitants and homes from air pollution.

FIGS. 2 and 3 show more in detail the heating unit of invention. A block of specially processed coal or charcoal 24 has been suitably molded as for example in a rectangular shape and provides a center opening or chimney 25 for admission of air at the center. The particles of specially processed coal or charcoal are conveniently bonded together by a suitable material such as molasses. To guard against damage from moisture and delay in lighting the block is coated on all its surfaces by a layer of paraffin 29. At the center and suitably near the upper part of the fuel block 24 is provided a block 26 of highly combustible material which surrounds and has molded in it an igniter filament 27 connected as by soldering to lead wires 28. The lead wires 28 are coated with a flammable insulation and are brought into intimate contact at 30 within or ad jacent to the highly combustible material 26 so that when the highly combustible material 26 is ignited by electric current passing through the filament the flammable insulation will burn and the intimately associated or twisted lead wires will short circuit. The outer ends of the lead wires are joined to series connector wires 31 which connect all of the igniters together in one series circuit as shown in FIG. 4. In this figure each igniter 32 is in series and the whole series is connected to an electric battery or other power source 33 through a switch 34 which when closed will ignite the igniters. It will be evident that the combustible material 26 does not burn explosively or very violently but burns like an ember for a relatively long period of time and lights the fuel block 24 which similarly burns slowly and over an extended period of time.

EXAMPLE 1 In a preferred embodiment the filament is a length of iron wire about 1 inch long with a diameter about 0.006 inch. This is joined as by soldering to copper lead wires of much higher cross section. The unit electrical resistance of the lead wires should not be more than 10 percent of that of the filament. The lead wires are insulated by a layer of plasticized pyroxylin. Camphor is an effective plasticizer. The length of the twisted portion of the pyroxylin insulation and lead wires should be at least two turns or about one-half inch of twisted wire.

The starter charge of combustible material 26 is preferably made as follows:

One hundred grams of dry sawdust are screened through a 16 mesh per linear inch screen and then thoroughly mixed with 25 grams of sodium nitrate dissolved in 100 cc. of water. The sawdust is dried and then mixed with 75 cc. of USP collodion (5 percent nitrocellulose solution in one volume of ethyl alcohol and three volumes of ether as a solvent). The

- through 16 mesh per linear inch bonded by 20 percent of weight of molasses. The coal is first partially charred to reduce smoke.

When the starter charge ignites it burns as an ember and ignites the fuel block which burns for a prolonged time as an ember.

Blocks of the character under discussion when connected together in series in groups of 50 can be readily ignited within a few minutes by a l2-volt battery. The electrical properties are not of a high degree of accuracy and the igniters do not ignite all at once but a particular igniter ignites and shorts out and then another, and another and so on until all igniters have ignited.

The starter charge and the fuel block of the invention are not subject to spontaneous combustion and are not readily ignited from a spark or a match unless the flame is held in contact with the fuel block or starter charge for a matter of several seconds.

EXAMPLE 2 In this case the flammable insulation is plasticized polystyrene or a styrene copolymer. A copolymer of butadiene and styrene (GRS) is preferred over polystyrene. While the pyroxylin type insulation is preferred, polystyrene is an effective insulator which will burn in the desired manner. In this case the fuel block is made of bituminous coal char.

EXAMPLE 3 In this case the fuel block is made of anthracite coal, milled with percent of its weight of sawdust and mixed with 5 percent of sodium nitrate or other oxidizing agent and with 12 percent of molasses as a binder, before compacting. This burns for a prolonged time.

EXAMPLE 4 in this case the fuel block is made of wood charcoal. All of these fuels are acceptable replacements for lignite coal.

EXAMPLE 5 The procedure of example 3 is followed except that green delayed petroleum coke replaces anthracite coal and the concentration of sodium nitrate is 7.5 percent by weight.

In view of my invention and disclosure, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. A series igniter chain and fuel device, comprising a plurality of igniters, connector wires connecting the igniters in se- .ries, each igniter having an electric filament, lead wires connected to the filament and to the connector wires and having insulation thereon, said insulation being flammable and the insulation being in intimate contact whereby on burning of the insulation the wires will short circuit one another, a block of combustible material surrounding each filament and in contact with the insulation to ignite the same, and fuel means adjacent to each combustible material for ignition thereby, whereby when a source of electrical energy of moderately low voltage is applied to the series igniter chains, some igniters ignite more rapidly than others and their lead wires short circuit, and thus the voltage is progressively increased on igniters which are slow to ignite in the chain.

2. A series igniter chain of claim 1, in which each pair of insulated lead wires is twisted together in the block of combustible material.

3. A series igniter chain ofclaim 1, In which each fuel means consists of a fuel block having a vertical chimney in which the block of combustible material is located. 

2. A series igniter chain of claim 1, in which each pair of insulated lead wires is twisted together in the block of combustible material.
 3. A series igniter chain of claim 1, in which each fuel means consists of a fuel block having a vertical chimney in which the block of combustible material is located. 